The news came as the News of The World’s chief reporter Neville Thurlbeck and former news editor Ian Edmondson were arrested as part of the ongoing phone hacking inquiry.

Bell Pottinger Public Affairs chairman Peter Bingle said: ‘Until the phone hacking story is finally laid to rest it will be a very brave client who lets it be known that they are being advised by Andy Coulson.

‘His skill as an operator is not in doubt. Unfortunately he remains the story.’

However, freelance public affairs consultant Lionel Zetter said Coulson's profile may not prove to be a significant problem for the business.

He said: ‘If notoriety were a bar to success then Lord Mandelson would not be enjoying the success he currently is. Both have been through the fire – and come out the other side stronger.’

Coulson’s agency is named after the highest mountain in Europe. One of his first clients is environmental organisation One Young World, which has been founded by Euro RSCG Worldwide UK group chairman Kate Robertson and Havas chief executive David Jones. Jones worked alongside Coulson during the last general election.